This paper argues against the grain of much recent work in environmental anthropology and related disciplines by pleading for a resurrection of the widely rejected distinction between Nature and Culture. In dialogue with Tim Ingold's 'relational-ecological-developmental' approach to human-environmental relations, the author discusses the role of culture and semiotic systems in two classical but very different problems of human ecology and human biology. The first concerns ecological explanations of food taboos in indigenous Amazonia, the second biological explanations of social differences in identity and behaviour. Both cases represent attempts to exclude the symbolic or cultural dimension from explanations of human behaviour, in the former case by arguing that it is macro-determined by ecosystems, and in the latter that it is micro-determined by genes. Finally, the paper suggests an analytical framework for more differentiated distinctions between those aspects of human bodies and landscapes that require semiotic or symbolic explanations and those that do not.